Benchmark: Fastest way to check if object is empty (3)

Tests:

object.keys()
var xxx = {} Object.keys(xxx) === 0
JSON.stringify()
var xxx = {} JSON.stringify(xxx) === "{}"
for let in
var xxx = {}; var isEmpty = true; for (let key in xxx) { isEmpty = false; break; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
object.keys()
JSON.stringify()
for let in

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
object.keys()	77749976.0 Ops/sec
JSON.stringify()	22727492.0 Ops/sec
for let in	101723672.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):

LLMs can make mistakes. Check important info.

The provided benchmark tests evaluate different methods for determining whether an object in JavaScript is empty. An empty object is defined as an object that has no enumerable properties. The benchmark compares three distinct approaches, each with its own pros and cons.

### Test Cases and Approaches

1. **Object.keys() Method**
   - **Benchmark Definition**: `var xxx = {}; Object.keys(xxx) === 0`
   - **Test Name**: `object.keys()`
   - **Description**: This method retrieves the keys of the object and checks if the resulting array's length is zero.
   - **Pros**:
     - Clear and straightforward approach.
     - Fulfills the requirement by checking the length of keys directly, making it easy to understand.
   - **Cons**:
     - Slightly less performant than a direct check since it creates an array of keys, which incurs some overhead.

2. **JSON.stringify() Method**
   - **Benchmark Definition**: `var xxx = {}; JSON.stringify(xxx) === "{}"`
   - **Test Name**: `JSON.stringify()`
   - **Description**: This method serializes the object to a JSON string and checks if this string is equal to the string representation of an empty object.
   - **Pros**:
     - Can be useful for debugging or logging since it provides a string representation of the object.
   - **Cons**:
     - Least performant of the three options due to the overhead of serialization, especially for larger objects. 
     - Not the most direct way to gauge if an object is empty, as it involves the potentially expensive stringify operation.

3. **For...in Loop**
   - **Benchmark Definition**: `var xxx = {}; var isEmpty = true; for (let key in xxx) { isEmpty = false; break; }`
   - **Test Name**: `for let in`
   - **Description**: This method iterates through the properties of the object, and if any exist, it breaks the loop and sets `isEmpty` to `false`.
   - **Pros**:
     - Operates directly on the object's keys without creating additional structures, making it very efficient in terms of performance.
   - **Cons**:
     - Slightly more verbose and less elegant than the `Object.keys()` method.
     - If not handled correctly (e.g., not checking for own properties), it could potentially produce incorrect results when dealing with prototype properties.

### Benchmark Results

From the benchmark results, we can see that:
- The `for...in` loop is the most performant approach, executing around **26 million times per second**.
- The `Object.keys()` method follows at approximately **19.9 million executions per second**, showing decent performance while remaining easy to read.
- The `JSON.stringify()` method lags significantly with only about **6.2 million executions per second**, indicating it’s the least efficient choice.

### Conclusions and Considerations

When selecting a method to check whether an object is empty:
- For optimal performance, especially in high-frequency calls or in performance-critical applications, the `for...in` loop is the best option.
- If code clarity and maintainability are the main concerns, `Object.keys()` provides a good balance between performance and readability.
- Avoid using `JSON.stringify()` purely for this purpose due to its inefficiency.

### Alternatives
Other potential alternatives could include:
- Using the `Reflect.ownKeys()` method to check for properties without creating an intermediate array, which can also yield good performance.
- For environments that support ES6 or later, the use of `Object.getOwnPropertyNames()` might also be considered, as it returns all properties, including non-enumerable ones, though it would also entail its own performance considerations.

Ultimately, the choice of method will depend on the specific context of use, taking into account factors such as performance, readability, and application architecture.

Related benchmarks:

Fastest way to check if object is empty (3) (version: 1)

You don't need to make add for loops in your test scenarios, the benchmark does it itself.

Comparing performance of: object.keys() vs JSON.stringify() vs for let in

Created: 3 months ago by: Guest

Jump to the latest result

object.keys()

JSON.stringify()

for let in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):